Find DNA Motifs in Seqqio: IUPAC Patterns, Regex, Overlaps, and Both Strands

The method is Seqqio-DnaPatternFind-v1. It is useful when the question can be stated as a sequence rule: “Where does CTTY occur?”, “Where is a C followed by one to four A/T bases and then G?”, or “Does this exact motif occur on either strand?” Keeping syntax, strand, overlap, and ambiguity policy beside the result prevents a coordinate list from losing its meaning.

Open DNA Pattern Find, select Single sequence or FASTA batch, and enter the DNA. Choose IUPAC motif for nucleotide codes or bounded regex for explicit pattern logic. Then set the strand, overlap behavior, and ambiguity policy before selecting Find patterns. The default motif is CTTY, searched on both strands with overlaps enabled and ambiguous input excluded.

Use the synthetic target AAACTTCTTGAAGTTT. Keep the default IUPAC motif CTTY, both strands, overlapping matches, and known-bases-only ambiguity. The Seqqio 0.1.0 Rust engine returned two hits: one forward occurrence at bases 4-7 and one reverse-complement occurrence at bases 10-13.

The original bases 10-13 are GAAG; their reverse complement is CTTC, which satisfies CTTY. Seqqio reports ascending coordinates on the original input for both strands, while the matched string is displayed in motif orientation. Forward hits appear before reverse hits. A palindrome can legitimately appear once per searched strand because those are separate strand events.

For IUPAC mode, known-bases-only requires the input position to be one concrete base. Possible-match accepts an ambiguous input when at least one possible base fits the motif. Certain-match accepts it only when every base represented by the input symbol fits. For motif A against input R, possible-match succeeds because R can be A, while known-only and certain-match fail. Motif N against input R succeeds under certain-match because every R possibility belongs to N.

These choices answer different questions; none resolves the underlying base. Record the policy with exported matches. The RCSB sequence-motif documentation illustrates why motif syntaxes need explicit conserved positions, alternatives, and flexible regions. The Biopython motif tutorial separately demonstrates reverse-complement motif searches.

Regex mode supports ASCII classes, groups, alternation, anchors, and finite greedy or lazy repetition with a maximum match span of 4,096 symbols. Use C[AT]{1,4}G instead of an unbounded expression when the biological or technical rule has a meaningful maximum. A regex match is still exact under the expression: it does not assign an edit distance, align gaps, calculate an E-value, or rank near matches.

If the job is to tolerate substitutions or insertions and deletions, use the Fuzzy DNA Search tutorial. Pattern Find and Fuzzy DNA Search may inspect the same target, but they answer different questions. Keeping their primary intents separate avoids treating a regular-expression wildcard as if it were an alignment model.

A matching string establishes only that the declared sequence rule occurs at the reported coordinates. It does not prove protein binding, promoter activity, restriction cleavage, conservation, expression, or regulatory function. Use annotations, comparative evidence, experimental context, and appropriate statistics for those conclusions. Zero matches is a successful search result and should remain visible in batch reports.

DNA Pattern Find is included in Seqqio's 39-application Windows 64-bit workspace. The Seqqio overview explains the local record, history, and export workflow. The complete toolkit is offered as a US$99 one-time purchase with no activation key.

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